Process of and apparatus for drying pervious material



Sept. 1. 1925. 1,552,099

- J. H. WALSH PROCESS OF AND APPARATUS FOR DRYING PERVIOUS MATERIAL Filed p il 14. 1922 s Sheets-Sheet 1 1 V a a a a a a a w @MMM M n m @@fi w? x M \Q vase ji waz u,

Sept. 1. 1925. 7 1,552,099

J. H. WALSH PROCESS OF AND APPARATUS FOR DRYING PERVIOUS MATERIAL Filed April 14, 922 3 Sheets-Sheet 2 r'illilllill Sept. 1, 1925.

J. H. WALSH- PROCESS OF AND APPARATUS FOR DRY-INGVPERVIOUS MATERIAL Filed April 14. 1922 s Sheets-Sheet 3 I drill/fl lrzrvfwrrrlw TENT OFFI JOSEPH H. WALSH, er rosrou, MAssAcnusEr'rs, assreuoa 'ro' Janus-mums,

mcoaronarnn, or NEW YORK, N. 2., a coaroaa'nou or NEW Yonx.

I rnocnss or m) arrana'rus r03 DRYING rmwrous MATERIAL.

Application flied April 14, 1922 Serial No. 552,725.

To all whom it may concern:

Be it known that I JosErH citizen of the United resident of Boston, in the county of Sui- H. WALSH, a

folk and State of Massachusetts, have in vented new and useful Improvements in Processes of and Apparatus for Drying Pervious Material, of which the'following is a specification.

- This'invention relates toa method of dry- "ing material and to apparatus useful in performing such method, and more particularly to a method'and apparatus especially useful for the economical and rapid removal of moisture from relatively thick but pervious sheet material such .for example as webs of textile fabric and the like. L

In the drying of textiles and particularly I relatively heavy and napped fabrics,"such for instance as blanket webs, it is difficult 'from a manufacturing standpoint to remove the moisture from the interior portionof the I material by the mere-application of a dry:

ingmedium to the surfaces thereof. While I 2 some gain in rapidity and thoroughness of drying may be secured by increasing the temperatureof the drying medium, it is evident that a limit is-soon reached beyond.

zwhich it is not possibleto 'go without dan-: ge'r of scorching the outer surfaces of the material, and inv fact at a muchlower temperature than this, the material sufiers substantial .detcrioration by reason, apparent.

.ly, of the formation of steam in the interstices of the fabric and the yarns of whichit is made resulting in the bursting apart of the yarns and breakage of fibres with damage to the quality of the fabric. Ina modern mill, Where the daily output is large, the problem of drying the. material without undue consumption of heat is one worthy of careful consideration, and while the general principles'involved in the ecojnomical use and conservation of heat have long been r'ecognized by engineers, little attempt has apparently been made heretofore to applysuch principles in a practical manner in the drying of heavy textile materials in commercial quantities.

rincipal object of the present invention 1s therefore to provide a method and apparatus whereby relatively thick but tates of America, and

pervious sheet material such for example as blanket cloth, may be dried rapidly and sumed' in the process may be reduced to a minimum.

In carrying this object into efl'ect, the web of material may be caused to traverse a predetermined. path, and at desired points in said path a current of warm air may bepassed transversely through the'interstices of the fabric from one sidefto the other side thereof. Preferably the same air is. caused to pass repeatedly through the fabric, the

incoming warm and relatively dry air first.

passing at a low velocity through that portionof the'web which has already parted with some of its moisture and in which the drying process is nearly complete, and thereafter causing such air to pass, preferably with increased yelocity, through the. wetter portions of the" web. Such warm and mois' ture laden air, through the fabric may then be passed through an economizer device where it parts with most of its heat to the incoming resh' air.

In the accompanying drawings there is illustrated, by way of example, one embodiment of means proper for carrying the invention into effect," and in such draw- Fig. 1 is .a longitudinal vertical sectionthrough the complete apparatus on a line 'such as 0:, '6 of Fig. 2;

Fig. 2 is a horizontal section on the line 0, d of Fig. 1;

Fig. 3 is a vertical cross section to somewhat larger 'sc'aleon the line e, f of Fig. 1; and

' Fig. 4 is a fragmentary typical section through a wall of the apparatus illustrating the-heat insulating structure.

The apparatus as herein illustrated comprises a housing consisting of the side walls 1, 2, the end walls '3, 4, and a to wall or roof 5. Preferably such walls an roof are ofheat insulating construction and ma consist as illustrated .in-Fi 4 of the stu s or joists 6, 811 outer sheat ing 7 of wood or other desirable" material, an mne'r sheath:

after its .final passage? ing 8 of asbestos wood or equivalent acidresistant, water-proof material, and an inner filling 9 of fibrous asbestos-or air cell sheet asbestos. When so constructed the housing serves to retain the heat of the drying medium introduced therein and to pre- A vent the loss ofsuch heat to the outside atmosphere. Spaced from the wall 4 of such housing is a second, auxiliary housing comprising the vertical side Walls 10, 11 and the end walls 12, 13, such Walls forming therebetween a chamber 14 which is open at its upper end. The wall 12 of this auxil- ,lary chamber is provided with an opening which may be supplied with any suitable heating medium whereby air drawn downwardly through the chamber 14 by the fan 17 may be raised in temperature prior to its discharge through the duct 15.

The upper wall 5 of the first named housing is extended rearwardly as indicated at 20 and is united to the upper portion of the wall 12, the member 20 forming the floor of an economizer device. This economizer device comprises the top wall or roof 21, the side walls 22, 23, and the end wall 24, the latter wall sloping downwardly from the front edge of the roof 21 and being united to the top edge of the wall 3. Within the chamber formed between the walls 21, 22, 23 and the 'flooi' member 20 is arranged a series of substantially parallel open-ended tubes or pipes .25. Preferably such tubes or pipes are of thin metal or other heat conducting material. These pipes, at their forward ends are seated in openins in a vertical partition 26 which exten s from the member 21 to the member 5, while at their rear ends such tubes pass through openings in a vertical extension of the wall 13. Im-- mediately to the rear of the partition 26 an' opening is formed in the top wall 'or roof 21 of the economizer device, and asspciated with such opening is a hood 2770f metal or othersuitable material. This" hood terminates in a flange orcollar 28 to which may be secured a pipe or conduit for leading air to the hood. .Within the economizer chamber a plurality of vertically disposed baflle plates 29 are preferably arranged, such plates ing so disposed as to compel air which enters through the hood 27 to flow a tor: tuous course in moving longitudinally throu h theeconomizer chamber.

Inlt jtop member 5 of the first mentioned housing and immediately below the wall 24 of the economizer device, an air egress opening 30 is formed. With the arrangement thus far described it will be clear that upon rotation of the fan 17, air will be drawn downwardly through the chamber 14 and forced through the duct 15 into the first named housing from which such air will escape through the egress opening 30 and will pass thence through the economizer tubes and will be discharged into the outside atmosphere as indicated by the arrows 31. At

the same time fresh air will be drawnthrough the hood 27 and will pass longitudinally of the economizer device and around tubes 25 so thatthe heat of theair passing through the tubes may be transferred to the incoming air.

Extending transversely across the first- -named housing and journalled in openings in the walls 1, 2 thereof is a shaft 32 upon,

which is mounted a drum consisting of the spaced heads 33 and 34, said heads being provided with radial pins or spurs 35 projecting'from their edges, such pins serving I to engage'the marginal portions of the fabric and hold it taut as it passes about the periphery of the drum.

Extending from the opening 16 at the lower part of the wall4 is a conduit comprisin the upper wall 36- and the lower wall 3 such walls'terminat-ing closely adjacent to the peripheral surface of the drum.

servmg to guide a web 42 of fabric as it enters the opening 39. A guide roll 43 may be provided exterior to the housing for directmg the-web of fabric toward the slot 39.

The rolls 40 and'41 are so disposed as to maintain the fabric in a plane parallel to the top wall 5 of the housing and very closely adjacent thereto, such fabric passing transversely across the opening 30. If de-' sired, and for maintaining a tight joint between the wall 5 and the fabric as the latter passes the opening, strips of felt or some similar material 3O may be caused to depend from the edges of the opening 30. Below the guide roll 41 is a guide roll 44 and, in

the included angle between the drum and the I .member 37 is another .guide roll 45. A

guide roll 46 is alsoarranged in the included angle between the drum and the member 36,

and in the wall 4 adjacent to the roll 46,

a secondslot 47 is provided for egress of the web of fabric from the housmg. A

, guide roll 48 may be provided for guiding the fabric as it emerges from the housing. As will be noticed, the arran ement'of the guide rolls and 46. is such t at the fabric 1s held closely against'the peripheral edges of the drum heads 34, 35, except at such portion of said edges as at any timelies ad- ]acent the air ingress opening 38.

In the operation of the device, the fabric entering through the slot 39 passes over the guide rolls 40 and 41 and transversely across is thus discharged is much greater than the cross sectional area of the duct 15. Thus the velocity of air passing outwardly from the drum through the fabric may be very slight as compared withits velocity in the duct 15. As the air emerges into'the housing after passing through the fabric .surrounding the drum, it' is free to circulate in contact with the horizontal runs of fabric between the rollers 40, 41 and the rollers 44, 45 respectively, as well as with the vertical run of fabric extending beneath the rollers 41 and 44. The air is unable to escape, however, from the housing except by passing through the fabric which extends across the egress opening 30 and as the area of such opening is relatively small as compared with the peripheral area of the drum, it isevident that the velocity of air through such opening and through fabric which lies immediately beneath the same mustbe substantially greater than its velocity on emerging from'the drum. After assing through the opening 30 the warm an moisture laden air escapes through the economizer tubes 25 in -the manner previously pointed out and during its passage through such tubes imparts some of its warmth to the incoming fresh air. The .air, after passing through the tubes 25 may, if desired, instead of being discharged into the open atmosphere, be conducted in any suitable manner to some point where warm and moist air is desirable, as for example the weave room of a mill. As the web of fabric passes the opening 30 soon after entering the housing, it isclear that at this point such web'is in a very .moist condition, so that the air escapin through the o ening 30 and which air has a ready receive some moisture, may-by reason of its high velocity, remove a substantial portion of the moisture from the web at this point.

As the web travels on, more moisture is absorbed by the air in the housing and as the 7 web passes abouithe drum, it is subjected to the action of be relatively slow moving but relatively hot air which emerges from.

the interior of such drum. It is thus clear that the drier portions of the web are traversed by slow moving and relatively Warm' currents of airwhile the wetter parts there.- of .are traversed by high velocity currents of an of a somewhat lower temperature and contalning a greater amount of moisture. The device-as thusflarran'ged is found to operate' in a highly eflicient manner, the ma terial emerging through the slot 47 being substantially dry even though the speed of travel of the web through the apparatus may be comparatively rapid. Theforcing of the air currents through the interstices-of the .material in a plurality of steps serves to re- While a preferred form of apparatus has been illustrated it will be understood that various changes and rearrangements of parts, as well as substitutions of equivalent materials. for those herein mentioned, may a be made without departing from the spirit of the invention.

What I claim anddesire to secure by Let-I ters Patentof the United States is:

1. That process of removing moisture from pervious material which comprises forcing a current of air to traverse the interstices of said material at arelatively high velocity and thereafter causing air to traverse the interstices of such material at a relatively low velocity.-

2. That process of dry ng pervlous material which comprises forcing a current of.

relatively cool and moist air at a relatively high velocity transversely through the interstices of the materiahand thereafter fore-fing a current of relatively hot and moisture absorbent air transversely through the material at a relatively low velocity.

3. That ocess of drying webs of textile fabric whic comprises subjecting such a web successively to air currents of successively decreased velocity, and successively increased temperature.

4. That process of fabric which. comprises passmg such through a heatinsulated chamber, causing drying webs of textile .a web ing the same air to traverse successive por-.

air at relatively low temperature and high velocity to pass transversely through such web adj acent to its point of entrance to the chamber, and causing warm air to. pass terial compr sing means for supporting the material to be treated, and means for forctions of the material at different velocities, the first passage of the air through the material being at the lower velocity.

7. An apparatus for'drying-websof tex-- tile fabric comprising means for guidin such a web for longitudinal movement, an means for causin air to traverse said material at a relatively high velocity at an early stage of its path of movement, and at a lower velocity at a later stage thereof.

8. Dr ing apparatus comprising means for gui 'ng a continuous web for movement in a predetermined path, and means for causing an air current of given volume, first 5 to pass through a relatively large area/of said web, and thereafter to pass through a relatively small area thereof. I

9. Drying apparatus of the class described comprising a heat insulated chamber prof vided with means whereby successive por- ,tions of a web traversing such chamber may be subjected to air currents 'of decreasing,

velocity, means for expelling warm an moisture laden air fromfsaid chamber, and means for causing fresh air to pass in heat transferring relationshi to such warm, moist air on its way to t e chamber. i

10. A drying ap aratus comprising a heat insulated-chamber avinge and ingress openings, means within 'said chamber for guiding a web of fabric whereb to cause it to pass successively across sai openings,

and .:'means for introducing a desi'cca'ting medium through said ingress opening whereby such medium is caused to traverse such web a plurality of times in; escaping from;

the egress opening.

11.. A drying apparatus comprising a chamber having egress and ingress openings,

means within said chamber for guiding-a web of fabric directly across the egress opening, other means for guiding such web in a circuitous path past the ingress openmg, and means for introducing warm air through said ingress opening.

12. Drying apparatus comprising a chamher having egress and ingress openings, a rotatable, peripherally open drum within said chamber, means for guiding a web of fabric across said egress opening'and. about said drum, and means for forcing warm air into the interior of said drum. I

13. Drying apparatus comprising a heat insulated chamber, a peripherally open drum rotatably mounted therein, said drum having closed ends means for guiding a Web of fabric peripherally about a substantial portion of the circumferential extent of said drum, and means for introducing warm air into said drum at a point where it is free from said w b. 3 u

14. Drying apparatus comprising a chamber having an air ingress opening, a drum rotatably mounted in said chamber, said drum comprising spaced heads having.-

fabric engagin elements, such elements constraining the abric to assure a cylindrical form, meansfor guiding a fabric webinto contact with such engaging elements except at that portion thereof which is o 'posite said ingress opening, and means for orcing air through said opening. I u

15. Drying apparatus comprising. a chamher having egress and ingress openings, a rotatable, peripherally open drum within said chamber constantly gress opening, means for retaining a web of material to be dried in close engagement with .f said drum wherebyto prevent escape of air therefrom except through the interwarm air through said ingress opening and into said drum. i

16. Drying apparatus comprising a heat jIinsulat'ed chamber, having an egress opening atone side and an ingress passage at vthe'opposite side, a" rotatable, peri herally open drum, guide rolls at-e'ither si e of the ingress .passagefo'rgholding a web of material closely against said drum, other guide rectly across said: egress opening, and means for forcing heated air through said ingress assa eand into the drum. 17 o rying apparatus compr sing a heat insulated housing having egress and ingress openings, an, economizer. comprising a series ref-parallel tubes communicating with said egress-openin a fan for inducing freshair to pass over t e outer surface of said tubes the interior of said drum beingin' communication with said ing 'stices of the fabric, and means for forcing iis whereby to take up heat fromflwarm .air

eating said incoming air and for directing it tosaid ingress opening, a peripherally open drum in said housing arranged transassing therethrough, means for further- 12tversely of said ingress opening, iiide rolls. 'for compelling a web of materia in traversing said chamber, closely to embrace said I rolls for compelling the web to travel di- 4 directl yhacross said egress opening.

irum except at that portion thereof extendof said web at successively decreasing vemg across the mgress opemn and ot er locities, and increasing the heat of the curgulde rolls for compelhn'g sal web to pass rent'of air prior to its first passage through 10 v the web of fabric. i 5 18. 0 art of drying webs of textile Signedby me alt Boston, Massachusetts, fabric comprising causing a) current of warm this twenty-eighthiday of J anuary, 1922.

air to pass through every part successively OSEPHH, WALSH. 

